Audio description

You might have used audio description on videos or DVDs with an AD marking. It works like a commentary for people who have difficulty seeing the screen. During the programme, a voice describes what's shown and what's happening on the screen during gaps in the dialogue.

AD is available on a wide range of digital TV products for use with an aerial, as well as on Sky and Virgin services. But note that it's not currently available on TalkTalk digital TV services that are delivered through your telephone line.

BSkyB satellite and the Virgin Media cable company broadcast audio description combined with a programme's soundtrack. You just have to change the settings on the TV - no special kit is needed. Further information is available from Sky Accessibility and Virgin Media customer services. You can also get more information on AD from RNIB.

Signing

Traditionally, with signed programmes you see a picture of a person signing in a corner of the screen. This is called 'open signing'.

Very few programmes are signed, and these are generally shown as repeats late at night. Yet over 50,000 deaf people in the UK use British Sign Language (BSL) as their first language.

Ofcom sets and monitors targets for broadcasters. The current 10-year target is for 5% of programming hours to be signed. This excludes commercial channels with less than 1% of audience share, which have a target of 30 minutes per month. Broadcasters are also required to raise awareness of this service and to identify signed programmes with 'SL' in on-screen TV guides.

Even with digital, you can only get just a few signed programmes. One of the problems is that open signing is expensive to produce, requiring a signer to be filmed separately from the programme. And, of course, non-users can find it intrusive on the screen.

Subtitling

Whatever TV you've got and whichever way you get a digital signal, you can get subtitles on a lot more channels than was possible with the old Teletext and Ceefax based analogue subtitles. Digital TV's new-style subtitles have a different typeface, size and positioning, chosen to be clearer and not block out key parts of the picture.

Ofcom sets and monitors targets for broadcasters. The current 10-year target is for 80% of programming hours to be subtitled. The free-to-air channels that are currently carrying the most programming with subtitles are: BBC One, BBC Two, BBC Three, BBC Four, Cbeebies, CBBC and BBC News 24 - about 100%; ITV, Channel 4 and Sky News - about 89%; Channel 5 - about 80%. Broadcasters are also required to raise awareness of this service.

Things to consider

All the products we tested could display subtitles when they were broadcast and, if they could record programmes, they could record subtitles. However, the following issues are worth bearing in mind:

Ideally, remote controls should have a 'subtitle' button; otherwise, subtitles are switched on and off via an on-screen menu, which is not so convenient.

Once subtitles have been selected, they stay on when you change channels with all the products we tested except only a couple of digital TVs and the BT Vision+ digital TV recorder (for advice, see BT's page: Turning on BT Vision subtitles).

Although we found no problems with pre-recorded subtitles, our testing detected problems with the smoothness of rapid live subtitles (such as those on live news reports) on several set-top boxes, digital TV recorders and TVs. This may be annoying for regular subtitle users, so you should check before buying.

Increasing the size of digital subtitles

The size of digital subtitles is largely the same whether you get your digital signal via an aerial, cable or satellite, and whatever the model of set-top box or recorder. However, for technical reasons, the new-style subtitles can't be enlarged in the same way as they used to be on some analogue TVs. This shouldn't be a problem if you're planning to buy a new TV because the key factor that affects the size of digital subtitles is the size of your TV screen, and modern flatscreen TVs can be bought in larger sizes. A bigger screen brings you a bigger picture and bigger subtitles.

If you're having trouble reading digital subtitles, you could:

Get some glasses specifically for TV viewing. Reading glasses and driving glasses focus at the wrong distance for TV viewing. Your optician can advise.

Buy a larger TV. Try viewing the subtitles on different size screens in a shop before buying.

If your TV has a 'zoom' setting, you may be able to enlarge the picture and still see all the lines of subtitles, but you'll miss the picture edges. It depends on your TV though: some don't have zoom; others can't display subtitles in zoom mode, or adjust it up and down. The zoom setting is usually in the menu under 'picture settings'.

If you're missing the bottom lines of subtitles:

Check the 'zoom' setting, usually found within the 'picture settings' menu on your TV. The zoom setting enlarges the picture beyond the size of the screen. It can mean that you'll miss the bottom of the picture and therefore one or more lines of subtitles.